if you have something that supports a newsfeed such as evolution or (I have been told gkrellm): I made a little something that generates an RDF file for it from emerge -up world

it has 2 main files

updateworld.cron which contains the commands to be executed (make sure it runs as root)

updateworld.py a python script that generates updateworld.rdf, the (local) newsfeed file to which you just have to point your client.

I use it to periodically check 'summary' in evolution to see if there are any newer packages for my box. right now every link points to gentoo.org I'll think about if I can give it any better functionality.

AFAIK it works, but I've only tested it myself due to lack of volunteers in the IRC channel :/